1 62 THE ANIMAL KINGDOM. 



the Nummulite, the largest animal of this group ; as is 

 also the stone taken from the Mokkadam range, of which 

 the great Egyptian Sphinx and the Pyramids are built. 

 The beautiful white limestone, of which so great a portion 

 of the buildings of Paris consist, and which is quarried in 

 the vicinity, owes its formation to the Milliola, the shell 

 of which is no larger than a millet seed. But even these 

 are not by any means the smallest forms of animal life, for, 

 according to Ehrenberg,*' there are above a million shells 

 of Foramenifera in every cubic inch of the chalk of 

 southern Europe, and far above ten millions in every 

 pound of chalk. It is from myriads of these minute 

 animals floating in the waters that the luminous appear- 

 ance of the sea is owing in the summer nights, for the 

 whole crowd emit phosphorescent rays, which make the 

 crested waves beam with light. 



Another group of animals, which seem precisely the same 

 in structure as the last, but which form their shells of Silex 

 (flint) instead of Calx (lime), are called Polycystina. 

 These have not the same tendency to form composite 

 structures, but are even more wonderful and more minute 

 than the others. It is quite impossible to describe the 

 marvellous variety or beauty of form of these shells. ! 

 have before me, under the microscope at this moment," 

 a slide with a circular cell, containing what appears 

 to be about as much very fine sand as could lie on the 

 point of your penknife. This comes from the rflck in 

 the island of Barbadoes, and when examined by means 

 of the light thrown upon the cell by the condenser, turn:-, 

 out to consist of innumerable shells, and of such infinite 

 variety that the slightest movement of the slide shows 

 an entirely new set ; and each one of these is perfect in 



* Ehrenbeig, Johann Gottfried, a distinguished German naturalist, born in 

 1795. He was famed for his microscopic observations in animal life. 



